elasticsearch plugin fixes.

[oxarbitrage]

From #1396 we have a few points left that will require research and implementation however we are out of time to do them in this release and they are not urgent.

• static variant serialization: add additional checks to adaptor for live chain sync #1396 (comment)
• code cleanup add additional checks to adaptor for live chain sync #1396 (review)

[abitmore]

Done via #2565. Closing.
BTW #2568 is the next work to be done.